US3013236A - Pressure responsive electrical instrument - Google Patents

Pressure responsive electrical instrument Download PDF

Info

Publication number
US3013236A
US3013236A US21254A US2125460A US3013236A US 3013236 A US3013236 A US 3013236A US 21254 A US21254 A US 21254A US 2125460 A US2125460 A US 2125460A US 3013236 A US3013236 A US 3013236A
Authority
US
United States
Prior art keywords
bellows
pressure
contact
pressure responsive
resistance element
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US21254A
Inventor
Marlan E Bourns
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Priority to US21254A priority Critical patent/US3013236A/en
Application granted granted Critical
Publication of US3013236A publication Critical patent/US3013236A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L9/00—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means
    • G01L9/0033—Transmitting or indicating the displacement of bellows by electric, electromechanical, magnetic, or electromagnetic means
    • G01L9/0035—Transmitting or indicating the displacement of bellows by electric, electromechanical, magnetic, or electromagnetic means using variations in ohmic resistance
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L13/00—Devices or apparatus for measuring differences of two or more fluid pressure values
    • G01L13/02—Devices or apparatus for measuring differences of two or more fluid pressure values using elastically-deformable members or pistons as sensing elements
    • G01L13/023—Devices or apparatus for measuring differences of two or more fluid pressure values using elastically-deformable members or pistons as sensing elements using bellows
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S73/00—Measuring and testing
    • Y10S73/10—Measuring and testing instrument mechanisms with acceleration compensation

Definitions

  • the present invention relates to differential pressure transducers of the type embodying an electrical signal means, such as a variable resistor or potentiometer, for measuring fluid pressure against either a vacuum, atmospheric pressure, or a second fluid pressure as the reference.
  • an electrical signal means such as a variable resistor or potentiometer
  • the primary object of the present invention is to provide a sensitive pressuretransducer which is relatively immune to the efiects, of shock, vibration, and acceleration. This is an important advantage, inasmuch as pressure transducers of this type arefrequently exposed to severe conditions of vibration and acceleration, while being called upon and deliver accurate pressure response, free of vibration and accelerationcrror.
  • Another object of the invention is to provide a pressure transducer of the type described, wherein the electrical output is not affected by temperature changes.
  • Still a further object of the invention is to provide a differential pressure responsive instrument which is simple and inexpensive to manufacture, while at the same time rugged in construction and having an extremely sensitive and accurate response to fluid pressure conditions.
  • the pressure transducer is designated in its entirety by the reference numeral Ill, and includes a housing consisting of a base 11 and cover 12.
  • the base 11 is preferably formed of dielectric material such as plastic, ceramic, or the like, and the cover 12 is a metal cup extending down over the edges of the base 11 and secured thereto by screws 13. Screwed into tapped holes in the bottom of the base 11 are two threaded pipes 14 and 15, which are connected to sources of fiuicl pressure (not shown).
  • tubular bushing 22 Mounted side by side within the housing and parallel to one another, are two thin-walled, pressure sensitive bellows 20 and 21, each of which is secured at one end thereof by a tubular bushing 22 to the base 11.
  • the tubular bushings 22 are secured within holes in the base 11, and the central bore of the bushing opens into the interior of its respective bellows.
  • the bottom end of the tubular bushing 22 opens into a short passageway 23 which connects into the associated pipe 14, 15, and the said pipes are thus connected to the interior of the bellows so that fluid pressure can be admitted thereto.
  • the top ends of the bellows 20, 21 are movable up and down responsive to changes in the pressure dilferential between the inside and outside of the bellows.
  • Secured to the movable end of each of the bellows is an upwardly projecting stud 24, having a socket 25 in its upper end to receive the shank 30 of one of two relatively movable parts comprising the electrical signal means 31.
  • Thesignal means 31 may take any desired form, but in the illustrated embodimentis shown as a potentiometer consisting of a resistance element 32. and wiper contact 33.
  • the resistance element 32 is mounted on the movable end of the bellows 21 and is elongated in configuration, with its lengthwise dimension, or longitudinal axis, extending parallel to the line of travel of the free end of the bellows.
  • the element 32 may take any desired form, but is here shown as a wire-wound type of element, which issecured to a support 34.
  • the support 34 is carried at the top end of the shank 30, which is mounted on the movable end of the bellows 21.
  • the wiper contact 33 is mounted on the movable end of the bellows 20, and is secured thereto by a s'upport'35.
  • the support 35 is mounted on the top end of the shank 30, which is attached to the stud 24 on the movable end of bellows 20.
  • the contact 33 is preferably formedof resilient sheet metal, and is in the form of a long slender finger with a flared root portion which isattached to the support 35.
  • the contact 33 projects laterally from the support 35 over the exposed surface of the resistance element 32.
  • a narrow ridge 36 on the end of the contact 33 wipes on the element 32 to make electrical contact therewith, and as the movable end of the bellows 29 travels up and down responsive to changes in pressure differential, the contact ridge 36 wipes on the element 32 from one end thereof to the other.
  • Wires 40 and 41 connect the ends of the resistance element 32 to terminals 42 and 43, respectively; the said terminals extending through holes in the cover 12 and being insulated therefrom by rubber grommets 44.
  • Contact member 33 is likewise connected by a wire 45 to a third terminal 46, which extends through a hole in the cover 12 and is insulated therefrom by a rubber grommet 47.
  • the two bellows 20 and 21 are preferably substantially identical in construction, and have substantially the same spring constant.
  • any vibration or acceleration forces applied to the instrument cause the element 32 and contact 33 to move up and down together in synchronism.
  • the electrical signal means is thus substantially unaffected by the effects of vibration or acceleration.
  • both of the bellows 2i? and 21 are exposed to the same temperature conditions, any change in the position of the contact 33 due to thermal effects is counteracted by a corresponding change in the position of the resistance element.
  • the instrument is thus relatively unaffected by temperature changes.
  • Fluid pressure may be introduced into either of the bellows 20 or 21 through pipes 14 or 15.
  • the other bellows may be evacuated and sealed, or opened to atmospheric pressure, or filled with gas or fluid at any desired pressure, depending upon the desired reference pressure.
  • the movable end of the bellows into which fluid pressure is admitted rises or falls with changes in the pressure dilierential between the inside and outside of the bellows. This causes the contact member 33 and element 32 to be displaced with respect to one another in the vertical direction, so that the contact 33 is shifted along the length of the element.
  • voltage is applied across the end of the resistance element 32, and the position of the wiper 33 along the length of the element is accurately shown by the voltage across terminal 46 and either of the terminals 42 or 43.
  • both of the bellows 20, 21, respectively in which case, both the element 32 and con tact 33 will be displaced in the vertical direction, and the resultant shift of the contact 33 along the length of the element 32 will be a function of the diflerence in pressures.
  • a differential pressure transducer comprising a housing, a pair of pressure sensitive bellows mounted on said housing, each of said bellows being independent of the other and having a free end movable in response to changes in the pressure differential between the inside and outside of said bellows, the free ends of said beilows moving in parallel paths, means for introducing two different fluid pressures from separate sot ces into said bellows, electrical signal means comprisig a resistance element mounted on the movable end of one of said bellows, and a contact member connected to the movable end of the other of said bellows, and terminal means electrically connected to said resistance element and to said contact member.
  • a differential pressure transducer comprising a housing having a base, a pair of. pressure sensitive bellows disposed side by side and parallel to one another, each of said bellows being independent of the other and having a fixed end attached to said base and a free end movable in response to changes in the pressure differential between the inside and outside of said bellows, said free ends of said bellows moving in parallel paths, means for introducing two different fluid pressures from separate sources into said bellows, an elongated resistance element mounted on the free end of one of said bellows, the longitudinal axis of said resistance element being parallel to the line of travel of said free end of said one beliows, a resilient spring contact finger fixed to the free end of the other of said bellows and projecting laterally therefrom, said contact finger extending tranversely across said resistance element and wiping thereon, and terminal means electrically connected to said resistance element and to said contact finger.

Description

Dec. 12, 1961 M. E. BOURNS 3,013,236
PRESSURE RESPONSIVE ELECTRICAL INSTRUMENT Original Filed June 14, 1956 INVENTOR. MARLAA/ E. Boumvs United States Patent j 3,613,236. a PRESSURE BESPQNSTVE. ELECTRICAL v ,IN3TRUMENT Marian E. Born-us, 2482 Carlton Place, Riverside, Calif. Continnatronof application Ser. "No. 591,370, June 14, 1956. This application Apr. 11, 1961?, Ser. No. 21,254 4'Claims. ((1338-41) The present invention relatesto pressure responsive electrical instrument, and is a continuation of my pendmg application, Serial No. 591,370, filed June i4, 1956, now Patent No. 2,932,807, entitled Pressure Responsive Electrical Instruments.
More specifically, the present invention relates to differential pressure transducers of the type embodying an electrical signal means, such asa variable resistor or potentiometer, for measuring fluid pressure against either a vacuum, atmospheric pressure, or a second fluid pressure as the reference.
The primary object of the present invention is to provide a sensitive pressuretransducer which is relatively immune to the efiects, of shock, vibration, and acceleration. This is an important advantage, inasmuch as pressure transducers of this type arefrequently exposed to severe conditions of vibration and acceleration, while being called upon and deliver accurate pressure response, free of vibration and accelerationcrror.
Another object of the invention is to provide a pressure transducer of the type described, wherein the electrical output is not affected by temperature changes.
Still a further object of the invention is to provide a differential pressure responsive instrument which is simple and inexpensive to manufacture, while at the same time rugged in construction and having an extremely sensitive and accurate response to fluid pressure conditions.
These and other objects and advantages of the present invention will become apparent to those skilled in the art upon consideration of the following detailed description of the preferred embodiment thereof, reference being had to the accompanying drawing, which is a cross sectional view taken through an instrument embodying the principles of the invention.
in the drawing, the pressure transducer is designated in its entirety by the reference numeral Ill, and includes a housing consisting of a base 11 and cover 12. The base 11 is preferably formed of dielectric material such as plastic, ceramic, or the like, and the cover 12 is a metal cup extending down over the edges of the base 11 and secured thereto by screws 13. Screwed into tapped holes in the bottom of the base 11 are two threaded pipes 14 and 15, which are connected to sources of fiuicl pressure (not shown).
Mounted side by side within the housing and parallel to one another, are two thin-walled, pressure sensitive bellows 20 and 21, each of which is secured at one end thereof by a tubular bushing 22 to the base 11. The tubular bushings 22 are secured within holes in the base 11, and the central bore of the bushing opens into the interior of its respective bellows. The bottom end of the tubular bushing 22 opens into a short passageway 23 which connects into the associated pipe 14, 15, and the said pipes are thus connected to the interior of the bellows so that fluid pressure can be admitted thereto.
The top ends of the bellows 20, 21 are movable up and down responsive to changes in the pressure dilferential between the inside and outside of the bellows. Secured to the movable end of each of the bellows is an upwardly projecting stud 24, having a socket 25 in its upper end to receive the shank 30 of one of two relatively movable parts comprising the electrical signal means 31.
3,913,236 Patented Dec. 12, 1961 Thesignal means 31 may take any desired form, but in the illustrated embodimentis shown as a potentiometer consisting of a resistance element 32. and wiper contact 33. The resistance element 32 is mounted on the movable end of the bellows 21 and is elongated in configuration, with its lengthwise dimension, or longitudinal axis, extending parallel to the line of travel of the free end of the bellows. The element 32 may take any desired form, but is here shown as a wire-wound type of element, which issecured to a support 34. The support 34 is carried at the top end of the shank 30, which is mounted on the movable end of the bellows 21.
The wiper contact 33 is mounted on the movable end of the bellows 20, and is secured thereto by a s'upport'35. The support 35 is mounted on the top end of the shank 30, which is attached to the stud 24 on the movable end of bellows 20. The contact 33 is preferably formedof resilient sheet metal, and is in the form of a long slender finger with a flared root portion which isattached to the support 35. The contact 33 projects laterally from the support 35 over the exposed surface of the resistance element 32. A narrow ridge 36 on the end of the contact 33 wipes on the element 32 to make electrical contact therewith, and as the movable end of the bellows 29 travels up and down responsive to changes in pressure differential, the contact ridge 36 wipes on the element 32 from one end thereof to the other..
Wires 40 and 41 connect the ends of the resistance element 32 to terminals 42 and 43, respectively; the said terminals extending through holes in the cover 12 and being insulated therefrom by rubber grommets 44. Contact member 33 is likewise connected by a wire 45 to a third terminal 46, which extends through a hole in the cover 12 and is insulated therefrom by a rubber grommet 47.
The two bellows 20 and 21 are preferably substantially identical in construction, and have substantially the same spring constant. Thus, any vibration or acceleration forces applied to the instrument cause the element 32 and contact 33 to move up and down together in synchronism. The electrical signal means is thus substantially unaffected by the effects of vibration or acceleration. Also, since both of the bellows 2i? and 21 are exposed to the same temperature conditions, any change in the position of the contact 33 due to thermal effects is counteracted by a corresponding change in the position of the resistance element. The instrument is thus relatively unaffected by temperature changes.
The operation of the present invention is believed to be more or less clear from the foregoing description and the drawing. Fluid pressure may be introduced into either of the bellows 20 or 21 through pipes 14 or 15. The other bellows may be evacuated and sealed, or opened to atmospheric pressure, or filled with gas or fluid at any desired pressure, depending upon the desired reference pressure. The movable end of the bellows into which fluid pressure is admitted rises or falls with changes in the pressure dilierential between the inside and outside of the bellows. This causes the contact member 33 and element 32 to be displaced with respect to one another in the vertical direction, so that the contact 33 is shifted along the length of the element. in the usual method of operation, voltage is applied across the end of the resistance element 32, and the position of the wiper 33 along the length of the element is accurately shown by the voltage across terminal 46 and either of the terminals 42 or 43.
If it is desired to measure the diiterence between two different fluid pressures, the two pressures may be admitted to the interiors of both of the bellows 20, 21, respectively, in which case, both the element 32 and con tact 33 will be displaced in the vertical direction, and the resultant shift of the contact 33 along the length of the element 32 will be a function of the diflerence in pressures.
While I have shown and described in considerable detail what I believe to be the preferred form of my invention, it will be understood by those skilled in the art that various changes may be made in the shape and arrangement of the several parts without departing from the broad scope of the invention, as defined in the appended claims.
1 claim:
1. A differential pressure transducer comprising a housing, a pair of pressure sensitive bellows mounted on said housing, each of said bellows being independent of the other and having a free end movable in response to changes in the pressure differential between the inside and outside of said bellows, the free ends of said beilows moving in parallel paths, means for introducing two different fluid pressures from separate sot ces into said bellows, electrical signal means comprisig a resistance element mounted on the movable end of one of said bellows, and a contact member connected to the movable end of the other of said bellows, and terminal means electrically connected to said resistance element and to said contact member.
2. A differential pressure transducer as defined in claim 1, wherein said two pressure sensitive bellows are substantially identical to one another and have substantially the same spring constant.
3; A differential pressure transducer comprising a housing having a base, a pair of. pressure sensitive bellows disposed side by side and parallel to one another, each of said bellows being independent of the other and having a fixed end attached to said base and a free end movable in response to changes in the pressure differential between the inside and outside of said bellows, said free ends of said bellows moving in parallel paths, means for introducing two different fluid pressures from separate sources into said bellows, an elongated resistance element mounted on the free end of one of said bellows, the longitudinal axis of said resistance element being parallel to the line of travel of said free end of said one beliows, a resilient spring contact finger fixed to the free end of the other of said bellows and projecting laterally therefrom, said contact finger extending tranversely across said resistance element and wiping thereon, and terminal means electrically connected to said resistance element and to said contact finger.
4. A ditferential pressure transducer as defined in claim 3, wherein said two pressure sensitive bellows are substantially identical to one another and have substantially the same spring constant.
References Cited in the file of this patent UNITED STATES PATENTS 1,398,792 Paulin Nov. 2?), 1921 2,542,717 Smith Feb. 20, 1951 2,622,177 Klose Dec. 16, 1952 2,889,527 Statham June 2, 1959
US21254A 1960-04-11 1960-04-11 Pressure responsive electrical instrument Expired - Lifetime US3013236A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US21254A US3013236A (en) 1960-04-11 1960-04-11 Pressure responsive electrical instrument

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US21254A US3013236A (en) 1960-04-11 1960-04-11 Pressure responsive electrical instrument

Publications (1)

Publication Number Publication Date
US3013236A true US3013236A (en) 1961-12-12

Family

ID=21803206

Family Applications (1)

Application Number Title Priority Date Filing Date
US21254A Expired - Lifetime US3013236A (en) 1960-04-11 1960-04-11 Pressure responsive electrical instrument

Country Status (1)

Country Link
US (1) US3013236A (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3145360A (en) * 1962-07-06 1964-08-18 Bourns Inc Electric pressure-responsive instrument
US3277720A (en) * 1963-12-03 1966-10-11 United Aircraft Corp Pressure sensor
FR2370270A1 (en) * 1976-11-08 1978-06-02 Bendix Corp MULTI-FUNCTION PRESSURE SENSOR
FR2420745A1 (en) * 1978-03-20 1979-10-19 Merlin Gerin Electrical switch pressure maintenance indicator - has bellows inside enclosure to move shaft with one end having transparent marked cover
US4358956A (en) * 1979-04-13 1982-11-16 Emdee Corporation Liquid level indicator

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1398792A (en) * 1918-04-10 1921-11-29 Paulin Josua Gabriel Pressure-gage log
US2542717A (en) * 1945-02-14 1951-02-20 Power Jets Res & Dev Ltd Means for measuring or indicating the ratio of two forces and applications thereof to mach number indicators
US2622177A (en) * 1951-05-17 1952-12-16 G M Giannini & Co Inc Angle-swept potentiometer
US2889527A (en) * 1957-01-07 1959-06-02 Statham Instrument Inc Electrical strain wire transducer

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1398792A (en) * 1918-04-10 1921-11-29 Paulin Josua Gabriel Pressure-gage log
US2542717A (en) * 1945-02-14 1951-02-20 Power Jets Res & Dev Ltd Means for measuring or indicating the ratio of two forces and applications thereof to mach number indicators
US2622177A (en) * 1951-05-17 1952-12-16 G M Giannini & Co Inc Angle-swept potentiometer
US2889527A (en) * 1957-01-07 1959-06-02 Statham Instrument Inc Electrical strain wire transducer

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3145360A (en) * 1962-07-06 1964-08-18 Bourns Inc Electric pressure-responsive instrument
US3277720A (en) * 1963-12-03 1966-10-11 United Aircraft Corp Pressure sensor
FR2370270A1 (en) * 1976-11-08 1978-06-02 Bendix Corp MULTI-FUNCTION PRESSURE SENSOR
US4131088A (en) * 1976-11-08 1978-12-26 The Bendix Corporation Multiple function pressure sensor
FR2420745A1 (en) * 1978-03-20 1979-10-19 Merlin Gerin Electrical switch pressure maintenance indicator - has bellows inside enclosure to move shaft with one end having transparent marked cover
US4358956A (en) * 1979-04-13 1982-11-16 Emdee Corporation Liquid level indicator

Similar Documents

Publication Publication Date Title
US3013234A (en) Pressure responsive electrical instruments
US2566369A (en) Pressure gauge
US2752558A (en) Electric transducer
US3022672A (en) Differential pressure cell
GB2059071A (en) Capacitive pressure transducer
US3013236A (en) Pressure responsive electrical instrument
US3068700A (en) Pressure responsive instruments
US3638481A (en) Pressure sensor
US3828294A (en) Acceleration transducer having semiconductive piezoresistive element
US2711463A (en) Tapped potentiometer element and associated network
US2443252A (en) Pressure operated rheostat
JPH05340963A (en) Acceleration signal generator
US2976506A (en) Pressure responsive electrical instruments
US2507501A (en) Pressure operated resistor
US3173120A (en) Potentiometric transducer
US2737051A (en) Pressure measuring device
US2484030A (en) Electrical deflectometer
US2743340A (en) Electrical resistor device
US2974531A (en) Accelerometer
US3196668A (en) Dual semiconductor strain gauges
US2839701A (en) Vacuum tube pick-up
US3308357A (en) Hydraulic/pneumatic to electric transducer
US2807167A (en) Pressure gage with temperature compensation
CA1091059A (en) Apparatus for measuring barometric pressure
US2638784A (en) Temperature sensing device